Bradbury is trying to show how this society is constantly bombarded with media. In this case, it's advertisements pounding them into a passive state. No one on the train is talking or interacting. They are just sitting listening to the advertisement like they are being brainwashed into buying denham's dentifrice. In contrast to this Montag is trying to read a passage from the Bible about letting go of material things (including Denham's dentifrice). This juxtaposition between the natural world and materialism further shows how society is so wrapped up in media that they are unaware of the world around them.
That they tried to comfort the girl
The answer you are looking for is credo
Sounds a bit like Christine- Also a novel by Stephen King
